Files
pysim/pySim/esim/rsp.py
Harald Welte af87cd544f osmo-smdpp: Implement eUICC + EUM certificate signature chain validation
Change-Id: I961827c50ed5e34c6507bfdf853952ece5b0d121
2024-01-22 19:08:09 +01:00

102 lines
4.5 KiB
Python

# Implementation of GSMA eSIM RSP (Remote SIM Provisioning)
# as per SGP22 v3.0
#
# (C) 2023-2024 by Harald Welte <laforge@osmocom.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from typing import Optional
import shelve
import copyreg
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.serialization import Encoding
from cryptography import x509
from collections.abc import MutableMapping
from pySim.esim import compile_asn1_subdir
asn1 = compile_asn1_subdir('rsp')
class RspSessionState:
"""Encapsulates the state of a RSP session. It is created during the initiateAuthentication
and subsequently used by further API calls using the same transactionId. The session state
is removed either after cancelSession or after notification.
TODO: add some kind of time based expiration / garbage collection."""
def __init__(self, transactionId: str, serverChallenge: bytes, ci_cert_id: bytes):
self.transactionId = transactionId
self.serverChallenge = serverChallenge
# used at a later point between API calsl
self.ci_cert_id = ci_cert_id
self.euicc_cert: Optional[x509.Certificate] = None
self.eum_cert: Optional[x509.Certificate] = None
self.eid: Optional[bytes] = None
self.profileMetadata: Optional['ProfileMetadata'] = None
self.smdpSignature2_do = None
# really only needed while processing getBoundProfilePackage request?
self.euicc_otpk: Optional[bytes] = None
self.smdp_ot: Optional[ec.EllipticCurvePrivateKey] = None
self.smdp_otpk: Optional[bytes] = None
self.host_id: Optional[bytes] = None
self.shared_secret: Optional[bytes] = None
def __getstate__(self):
"""helper function called when pickling the object to persistent storage. We must pickel all
members that are not pickle-able."""
state = self.__dict__.copy()
# serialize eUICC certificate as DER
if state.get('euicc_cert', None):
state['_euicc_cert'] = self.euicc_cert.public_bytes(Encoding.DER)
del state['euicc_cert']
# serialize EUM certificate as DER
if state.get('eum_cert', None):
state['_eum_cert'] = self.eum_cert.public_bytes(Encoding.DER)
del state['eum_cert']
# serialize one-time SMDP private key to integer + curve
if state.get('smdp_ot', None):
state['_smdp_otsk'] = self.smdp_ot.private_numbers().private_value
state['_smdp_ot_curve'] = self.smdp_ot.curve
del state['smdp_ot']
return state
def __setstate__(self, state):
"""helper function called when unpickling the object from persistent storage. We must recreate all
members from the state generated in __getstate__ above."""
# restore eUICC certificate from DER
if '_euicc_cert' in state:
self.euicc_cert = x509.load_der_x509_certificate(state['_euicc_cert'])
del state['_euicc_cert']
else:
self.euicc_cert = None
# restore EUM certificate from DER
if '_eum_cert' in state:
self.eum_cert = x509.load_der_x509_certificate(state['_eum_cert'])
del state['_eum_cert']
# restore one-time SMDP private key from integer + curve
if state.get('_smdp_otsk', None):
self.smdp_ot = ec.derive_private_key(state['_smdp_otsk'], state['_smdp_ot_curve'])
# FIXME: how to add the public key from smdp_otpk to an instance of EllipticCurvePrivateKey?
del state['_smdp_otsk']
del state['_smdp_ot_curve']
# automatically recover all the remainig state
self.__dict__.update(state)
class RspSessionStore(shelve.DbfilenameShelf):
"""A derived class as wrapper around the database-backed non-volatile storage 'shelve', in case we might
need to extend it in the future. We use it to store RspSessionState objects indexed by transactionId."""
pass